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本文对使用胶黏剂对采用超塑成形/扩散连接工艺的钛合金零件表面沟槽的可行性进行了评估,以某钛合金气动面为例设计了填补沟槽的试验验证过程,试验结果表明使用胶黏剂对零件表面沟槽进行填补是可行的。 相似文献
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《航空学报》2017,(12)
对采用电子束表面微造型技术加工的TC4钛合金非光滑表面进行了研究。研究发现,通过该技术加工的非光滑表面具有截面为波浪形的沟槽,而且通过调节加工参数,可制备不同尺寸特征的沟槽。加工的沟槽沟脊处存在连续分布的鱼鳞状形貌,而沟谷处存在连续分布的倒V形条纹,鱼鳞形貌大小和V形条纹的间距均与加工参数有关。加工后的近表面从上至下由熔化区、热影响区和母材组成,熔化区由马氏体组成,热影响区位于熔化区和母材之间,其微观组织与母材也存在很大差异。熔化区和热影响区的显微硬度均要高于母材,而且在熔化区和热影响区的界面处存在显微硬度的最大值。电子束表面微造型的减阻效果可以达到15%以上。 相似文献
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基于鲨鱼皮衍生出来的微观仿生表面被广泛应用于机翼等航空零部件的设计中,对于提高航空零部件的疲劳寿命、气流动力性等服役性能具有重要作用。砂带磨削能实现零部件表面的高完整性要求的加工,故常用于叶片、整体叶盘等复杂曲面的精密磨削,且能实现微观表面形状,但目前缺乏砂带磨削微观表面的系统研究从而难以实现其精确控制。首先,分析了微观仿生锯齿状表面的典型结构特征,基于单颗粒砂带磨削模型,研究了单颗粒砂带磨削去除机理;然后,建立了砂带磨削多颗粒参数化数学模型,提出了微观仿生锯齿状表面砂带磨削方法;最后,以钛合金叶片型面为对象,搭建以钛合金为典型材料的微观仿生锯齿状表面砂带磨削基础实验平台,进行仿生表面的实验验证。通过对磨削后叶片的表面微观形状参数进行检测,结果表明通过砂带磨削方法实现的微观仿生锯齿状表面以锯齿形沟槽为主,其中沟槽的宽度在2.5~8 μm之间、平均值为4.91 μm,沟槽的高度在3.5~9 μm之间、平均值为5.91 μm,沟槽的夹角在28°~68°之间、平均值为42.3°,验证了微观仿生锯齿状表面砂带磨削的可行性。 相似文献
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钛合金表面镍基喷焊涂层的组织和耐磨行为 总被引:7,自引:0,他引:7
采用火焰喷焊技术对钛合金表面进行耐磨改性,可以较好地解决实施工艺过程中的工程适应性问题,但对于任何一种表面耐磨处理技术,耐磨性能的改善和提高都是其最终目的。考察了钛合金表面上3种不同成分的镍基火焰喷焊涂层的组织和耐磨行为。研究发现,3种成分的镍基涂层都具有韧基体+硬质相的耐磨组织,其基体均为强韧性很好的镍基固溶体,但硬质相的差别较大。在相同试验条件下,100%的F102涂层、含4%La2O3的稀土复合涂层和含25%WC的N i-WC复合涂层的磨损失重仅为未处理钛合金的1/6,1/8和1/10。试验结果表明,采用火焰喷焊技术对钛合金表面进行耐磨处理,可以有效地改善表面的耐磨性。 相似文献
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《燃气涡轮试验与研究》2017,(4)
为研究航空发动机压气机钛合金构件发生钛火的形成机理和影响规律,围绕试验件设计、参数测试与状态调控等关键技术进行深入探索,完善了可变环境条件下的钛合金旋转摩擦试验方法,并在此基础上开展了试验件结构、材料与气流参数对钛合金燃烧特性影响的试验研究。试验结果表明:双环结构试验件具有较好的强度和刚度,能够满足钛合金摩擦试验要求;在试验工况范围内,TC4钛合金材料较Ti40材料更容易燃烧,且气流参数对钛合金燃烧特性的影响不明显。 相似文献
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The effect of inlet conditions on the flow and heat transfer in multiple rotating cavity with axial throughflow 总被引:1,自引:0,他引:1
This paper discusses experimental results from two different build configurations of a heated multiple rotating cavity test rig.Measurements of heat transfer from the discs and tangential velocities are presented.The test rig is a 70% full scale version of a high pressure compressor stack of an axial gas turbine engine.Of particular interest are the internal cylindrical cavities formed by adjacent discs and the interaction of these with a central axial throughflow of cooling air.Tests were carried out for a range of non-dimensional parameters representative of high pressure compressor internal air system flows(Re up to 5×106 and Rez up to 2×105).Two different builds have been tested.The most significant difference between these two build configurations is the size of the annular gap between the(non-rotating) drive shaft and the bores of the discs.The heat transfer data were obtained from thermocouple measurements of surface temperature and a conduction solution method.The velocity measurements were made using a two component,LDA system.The heat transfer results from the discs show differences between the two builds.This is attributed to the wider annular gap allowing more of the throughflow to penetrate into the cavity.There are also significant differences between the radial distributions of tangential velocity in the two builds of the test rig.For the narrow annular gap,there is an increase of non-dimensional tangential velocity V/Ωr with radial location to solid body rotation V/Ωr=1.For the wider annular gap,the non-dimensional velocities show a decrease with radial location to solid body rotation. 相似文献
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Research on Auto-detection for Remainder Particles of Aerospace Relay Based on Wavelet Analysis 总被引:2,自引:0,他引:2
GAO Hong-liang ZHANG Hui WANG Shu-juan 《中国航空学报》2007,20(1):75-80
Aerospace relay is one kind of electronic components which is used widely in national defense system and aerospace system. The existence of remainder particles induces the reliability declining, which has become a severe problem in the development of aerospace relay. Traditional particle impact noise detection (PIND) method for remainder detection is ineffective for small particles, due to its low precision and involvement of subjective factors. An auto-detection method for PIND output signals is proposed in this paper, which is based on direct wavelet de-noising (DWD), cross-correlation analysis (CCA) and homo-filtering (HF), the method enhances the affectiv-ity of PIND test about the small particles. In the end, some practical PIND output signals are analysed, and the validity of this new method is proved. 相似文献
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YANG Fen ZHANG Xue-jun TIAN Fang WU Xu GAN Fu-xing 《中国航空学报》2007,20(2):181-186
Antimony-doped tin hydroxide colloid precipitates have been synthesized by hydrolysis of SnCl4 and SbCl3 using: (1) an ion-exchange hydrolysis to remove chlorine ions, and (2) isoamyl acetate as an azeotropic solvent to obviate water. The obtained dried powder is of high dispersivity without any need for further grinding. The size and dispersivity of the final particles are investigated with the aid of TG-DTA, BET, XRD and TEM. After having calcined, the antimony-doped tin oxide nanopowder possesses a tetragonal rutile structure with high dispersivity, uniform particles and low hard agglomeration. 相似文献
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Effects of Mo on the Microstructure and Hydrogen Sorption Properties of Ti-Mo Getters 总被引:1,自引:0,他引:1
ZHOU Hong-guo WEI Xiu-ying MAO Chang-hui XIONG Yu-hua QIN Guang-rong 《中国航空学报》2007,20(2):172-176
The effects of Mo on the microstructure evolution, porosity and hydrogen sorption properties of Ti-Mo getters are investigated in this work. The results show that the addition of Mo prolongs the densification process of Ti-Mo getters and results in a significant amount of sintered pores. With the Mo content increasing, the porosity of getters firstly increases reaching the maximum value as it at- tains about 7.5wt.%, and then drops. At the room temperature, the hydrogen sorption property of getters increases progressively with the Mo content increasing, but the tendency is not very clear before its content lies below 2.5wt.%. When the Mo content achieves about 7.5wt.%, the hydrogen sorption property proves to be the best. The discussion is made about the above mentioned phenomena inclusive of hydrogen sorption properties of getters under different activation conditions (from 500-750 ℃). 相似文献
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超声速燃烧数值模拟中的湍流与化学反应相互作用模型 总被引:1,自引:0,他引:1
高精度数值模拟有助于理解超声速湍流燃烧中湍流与化学反应的相互作用,可为发动机燃烧室等工程应用设计提供可靠的预测模型。除直接数值模拟外,目前在湍流燃烧应用中使用的大涡模拟和雷诺平均Navier-Stokes模拟均需要借助模型模化发生在湍流小尺度上的流动与化学反应过程对湍流大尺度运动的影响。现有的湍流与化学反应相互作用模型大致可分为:火焰面类模型和概率密度函数类模型,2类模型在不同的应用中各自具有优势和局限性。此外,现有模型大都基于低马赫数燃烧,而超声速燃烧中通常会伴随快速混合、局部熄火和再着火以及激波等复杂过程,这为发展其中的湍流与化学反应相互作用模型提出了更多的挑战。 相似文献
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适于低轨卫星IP网络的单核共享树组播算法(英文) 总被引:1,自引:0,他引:1
为了解决低轨卫星IP网络中现有典型源组播算法的信道资源浪费问题,本文提出了一套单核共享树组播算法,即核心群合并共享树(CCST)和加权核心群合并共享树(w-CCST)算法。CCST 算法包括动态近似中心(DAC)选核方法和核心群合并组播路径构建方法。DAC方法专为周期、规律运动的低轨卫星网络提出,不需要复杂的星上计算。在核心群合并方法中,以核节点作为初始核心群,通过核心群和剩余组成员的最短路径方法逐步扩展直至整棵组播树构建完成,从而使得组播树的树代价最小,大大提高了网络的带宽利用率和组播传输效率。w-CCST 算法中所提出的加权因子可以调整树代价和端到端传播时延之间的折衷程度,因此,可以通过调整加权因子来适度增大树代价、降低端到端传播时延以支持某些端到端时延要求苛刻的实时组播业务。最后,与低轨卫星 IP 网络中典型算法进行了性能比较,仿真结果说明,CCST 算法的平均树代价比其它算法显著降低,w-CCST 算法的平均端到端传播时延小于 CCST 算法。 相似文献
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Jet Vectoring Control Using a Novel Synthetic Jet Actuator 总被引:3,自引:1,他引:2
LUO Zhen-bing XIA Zhi-xun XIE Yong-gao 《中国航空学报》2007,20(3):193-201
A primary air jet vectoring control system with a novel synthetic jet actuator (SJA) is presented and simulated numerically. The results show that, in comparison with an existing traditional synthetic jet actuator, which is able to perform the duty of either “push” or “pull”, one novel synthetic jet actuator can fulfill both “push” and “pull” functions to vector the primary jet by shifting a slide block inside it. Therefore, because the new actuator possesses greater efficiency, it has potentiality to replace the existing one in various appli- cations, such as thrust vectoring and the reduction of thermal signature. Moreover, as the novel actuator can fulfill those functions that the existing one can not, it may well be expected to popularize it into more flow control systems. 相似文献
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Nonlinear Adaptive Slewing Motion Control of Spacecraft Truss Driven by Synchronous V-gimbaled CMG Precession 总被引:1,自引:0,他引:1
Zhou Di Zhou Jingyang 《中国航空学报》2007,20(4):332-338
The slewing motion control of a truss arm driven by a V-gimbaled control-moment-gyro (CMG) is a nonlinear control problem. The V-gimbaled CMG consists of a pair of gyros that must precess synchronously. The moment of inertia of the system, the angular momentum of the gyros and the external disturbances are not exactly known. With the help of feedback linearization and recursive Lyapunov design method, an adaptive nonlinear controller is designed to deal with the unknown items. Performance of the proposed controller is verified by simulation. 相似文献
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LI Yue-jun YAN Chao 《中国航空学报》2007,20(3):202-209
A new time-accurate marching scheme for unsteady flow calculations is proposed in the present work. This method is the combination of classical Successive Over-Relaxation (SOR) iteration method and Jacobian matrix diagonally dominant splitting method of LUSGS. One advantage of this algorithm is the second-order accuracy because of no factorization error. Another advantage is the low computational cost because the Jacobian matrices and fluxes are only calculated once in each physical time step. And, the SOR algorithm has better convergence property than Gauss-Seidel. To investigate its accuracy and convergency, several unsteady flow computa- tional tests are carried out by using the proposed SOR algorithm. Roe’s FDS scheme is used to discritize the inviscid flux terms. Un- steady computational results of SOR are compared with the experiment results and those of Gauss-Seidel. Results reveal that the numerical results agree well with the experimental data and the second-order accuracy can be obtained as the Gauss-Seidel for unsteady flow computations. The impact of SOR factor is investigated for unsteady computations by using different SOR factors in this algorithm to simulate each computational test. Different numbers of inner iterations are needed to converge to the same criterion for different SOR factors and optimal choice of SOR factor can improve the computational efficiency greatly. 相似文献